The synthesis of new geometrically frustrated layered systems has fueled experimental work and progress in building models of low-dimensional magnetism. Compounds with the structure of the francisite mineral, Cu₃Bi(SeO₃)₂O₂Cl, are quasi-two-dimensional antiferromagnets with a kagome-type lattice. With the dominant ferromagnetic interaction in the layer and a weak interlayer antiferromagnetic bond, the main noncollinear state of francisite is easily destroyed by an external magnetic field, which opens the possibility of reversible switching between states with the minimum and maximum possible magnetization. In the region of metamagnetic transition, multiferroelectric effects and broadband absorption of electromagnetic waves are observed. The implantation of rare-earth ions R into the Bi position is accompanied by spin-reorientation phase transitions in Cu₃ R(SeO₃)₂ O₂ X compounds, where X = Cl, Br.

新的几何受挫分层系统的合成推动了低维磁性模型构建的实验工作和进展。具有方石英矿物结构的化合物，Cu ₃ Bi(SeO ₃ ) ₂ O ₂Cl是具有kagome型晶格的准二维反铁磁体。由于层中主要的铁磁相互作用和弱的层间反铁磁键，方铁矿的主要非共线状态很容易被外部磁场破坏，这开启了在具有最小和最大可能磁化强度的状态之间可逆切换的可能性。在变磁跃迁区域，观察到多铁电效应和电磁波的宽带吸收。稀土离子R注入 Bi 位置伴随着 Cu ₃ R (SeO ₃ ) ₂ O ₂ X化合物中的自旋重定向相变，其中X = 氯，溴。